MIDTERMS

• Endocrine System


  Organs whose secretions (hormones) are poured into blood to reach target cells
• Endocrine glands


  • Made of cluster secretory cells "ACINI"
  • No ducts
  • Rich blood supply
• Negative feedback mechanism


  Way of regulating hormone concentration in the bloodstream
• Hormonal regulation


  Hypothalamic-endocrine axis
• Pancreas secretes insulin and is part of the Digestive System
• Parathyroid regulates Calcium and Phosphorus deposition and release in bone
• Blood Sugar Homeostasis


  1. Increased: Pancreas secretes insulin, blood glucose stored in liver

  2. Decreased: Pancreas breaks down glucagon, blood glucose homeostasis
• Posterior Pituitary stores oxytocin and ADH directly in the blood
• Hypothalamic-Pituitary-Endocrine Linkages


  1. Bone- GH

  2. Adrenal Cortex- ACTH

  3. Thyroid- TSH

  4. Ovary & Testes- Gonadotropic Hormones

  5. Skin- Melanocyte Stimulating Hormones

  6. Mammary Glands- prolactin & oxytocin

  7. Uterus smooth muscles- oxytocin

  8. Kidney Tubules- ADH
• Hypothalamus


  Controls release of pituitary hormones
• Pituitary


  • HYPOPHYSIS
  • Master gland
  • Round structure, 1.27 cm located at inferior aspect of the Brain
  • Controlled by Hypothalamus

  
• Anterior Pituitary Hormones


  • Growth hormone (GH)
  • Thyroid Stimulating Hormone (TSH)
  • Adrenocorticotropic Hormone (ACTH)
  • Follicle Stimulating Hormone (FSH)
  • Luteinizing Hormone (LH)
  • Prolactin
  • Melanocyte Stimulating Hormone (MSH)
• Growth Hormone


  Increases protein synthesis, breakdown of fatty acids, blood glucose levels, needed for normal growth
• Posterior Pituitary


  • Stores ADH (Vasopressin) and Oxytocin
• ADH (Vasopressin)


  Increases water reabsorption by kidney, stimulated by increased blood osmolality or low blood pressure
• Oxytocin


  Facilitates milk ejection during lactation, uterine contraction during labor and delivery
• Pineal Gland


  Secretes melatonin, controls circadian rhythms, triggered by darkness and inhibited by light
• Thyroid Gland


  • Butterfly-shaped, 5cm long and 3cm wide, 30g, located in lower part of anterior neck, high blood flow
• Calcitonin


  Reduces plasma calcium level by increasing bone deposition and decreasing bone resorption
• T3


  5x more potent than T4, rapid cellular metabolic activity, needed for cell replication and brain development
• T4


  Weaker than T3, controls body metabolism
• Iodine is needed for thyroid hormone synthesis
• Adrenal Gland


  Pair of glands resting on top of each kidney with 2 layers, regulated by Hypothalamic-Pituitary-Adrenal Axis
• Adrenal Cortex Hormones


  • Glucocorticoids (Cortisol)
  • Mineralocorticoids (Aldosterone)
  • Androgens (sex hormones)
• Glucocorticoids (Cortisol)


  Signals brain, regulates glucose metabolism, inhibits inflammation and immune response
• Mineralocorticoids (Aldosterone)


  Regulates sodium and water retention
• Adrenal Medulla


  Functional part of the Autonomic Nervous System, secretes catecholamines (90% epinephrine, 10% norepinephrine)
• Pancreatic Islet Cells


  • Alpha- Glucagon
  • Beta- Insulin
  • Delta- Somatostatin (Inhibitory)
• Pancreatic Insulin


  Allows glucose to enter cell membrane, not needed for islet cells
• Pancreatic Glucagon


  Increases blood glucose levels through glycogenesis and glucogenolysis
• Testicular Cells


  • Leydig Cells- Androgen (Testosterone, Dehydrotestosterone, Androsterone)
  • Maintain function of reproductive organs, secondary sex characteristics, male libido
• Ovarian Cells


  • Follicular Cells- Estrogen
  • Corpus Luteum- Progesterone
• Estrogen


  Develops uterine and mammary glands, maintains structure of external genitalia, produces secondary sexual characteristics in females, regulates normal menstrual cycle
• Progesterone


  Maintains normal menstruation, increases body temperature, decreases muscle tone and peristalsis, maintains pregnancy
• Renin-Angiotensin-Aldosterone System (RAAS)


  1. Hypothalamus signals Pituitary

  2. Spinal Cord secretes Epinephrine

  3. Signals Kidney to release Renin

  4. Renin converts Angiotensin I to Angiotensin II

  5. Angiotensin II stimulates Aldosterone release

  6. Aldosterone retains Sodium and releases Potassium, increases Blood Pressure
• Hypopituitarism


  Low secretion of pituitary gland or disease of hypothalamus
• Causes of hypopituitarism


  • Congenital
  • Trauma
  • Radiation of pituitary gland
  • Infection & Tumor
• Hypopituitarism


  • Atrophy of all endocrine glands
  • Dwarfism- ↓ GH
  • Low intellectual development
  • Poor development of secondary sexual characteristics
  • Hemianopsia- loss of peripheral vision
  • Hypothyroidism
  • Amenorrhea, impotence
  • Adrenal Insufficiency

  
• Nursing interventions for hypopituitarism

  1. Provide emotional support to the family

  2. Encourage patient and family to express feelings

  3. Administer prescribed hormonal replacement therapy

  4. Hypophysectomy
• Hypophysectomy


  Removal of pituitary gland